Lens Material Flashcards
1
Q
Index
A
Thickness of material (high index = thinner material)
2
Q
Specific gravity
A
Refers to the weight
3
Q
Abbe
A
Hardness of material
4
Q
CR-39
A
High Abbe w/ standard index
5
Q
Polycarbonate
A
Low Abbe
Easily scratched
High index = impact resistance
6
Q
Hi-Index Plastic
A
High index
Indices of 1.60, 1.66 and 1.71, 1.74
7
Q
Trivex/Phoenix/trilogy
A
High Abbe
Excellent quality
Lightest lens available
Impact resistance
8
Q
Crown Glass
A
High Abbe
1.52 index
Standard by which all material are measured
9
Q
Photochromatic glass
A
Very hard
Changes colour when exposed to light
Available in plastic or glass
